This invention relates to improved gas power sources for a needle-less injector, and in particular, embodiments for providing gas power to a needle-less injector and needless-less injectors with greater reliability and at reduced manufacturing cost.
Typically, needle-less medication injections are performed with xe2x80x9cpermanent gunxe2x80x9d instruments, generally referred to as xe2x80x9cjet injectorsxe2x80x9d. These devices use either a compression spring or a compressed inert gas to propel the fluid medication (via a push rod plunger) through a small orifice (an injector nozzle) which rests perpendicular to and against the injection site. The fluid medication is generally accelerated at a high rate to a speed of between about 800 feet per second (fps) and 1,200 fps (approximately 244 and 366 meters per second, respectively). This causes the fluid to pierce through the skin surface without the use of a needle, resulting in the medication being deposited in a flower pattern under the skin surface. This method of medication delivery is referred to as a subcutaneous injection.
Conventional, reusable jet injectors are cumbersome and awkward to use. Preparing a typical, reusable jet injector for administering an injection requires several steps. For example, prior to each injection, the injector nozzle must be sterilized. The operator removes the delivery nozzle from the jet injector and boils the nozzle in water to assure a reasonable degree of sterilization. After the nozzle is cleaned, the user replaces it on the instrument and prepares the instrument for loading the medication which is to be injected into the skin. A concern often associated with the nozzle in these reusable systems is that, due to a relatively small opening (approximately 0.004xe2x80x3 or less), the nozzle has a tendency to clog up if the device is left unused for a period of time or if the user does not clean the instrument each time after being used and prior to its reuse.
In addition, loading known reusable jet injectors with medication is a time consuming and delicate operation. First, an adapter which contains a needle is placed through the rubber septum of the medication vial. The nozzle of the jet injector is then mated to the needle adapter in the medication vial. The operator then proceeds to draw up medication into the delivery chamber of the jet injector. This operation may be repeated several times, until the trapped air in the delivery chamber is removed. When this pre-injection operation is complete, the operator selects an injection site and administers the injection.
However, a used and worn delivery orifice can slow down the delivery speed of the injected fluid, which results in inadequate penetration and causes bruising of the skin at the injection site. In addition, the improper use of jet injectors creates bruising (subdermal hematoma) when the nozzle is not firmly pressed against the injection site. Bruising also may occur if the nozzle opening (orifice) is partially clogged or worn out.
Conventional jet injectors are also somewhat dangerous to use, since they can be discharged without being placed against the skin surface. With a fluid delivery speed of about 800 fps or higher, a jet injector could injure a person""s eye at a distance of up to 15 feet. It should also be noted that jet injectors which have not been properly sterilized are notorious for creating infections at the injection site. In addition, if a jet injector is not positioned properly against the injection site, the injection can be short of the measured dosage, thereby creating wetting on the skin surface, which leads to additional problems associated with improper dosage amounts.
Moreover, it should also be noted that compression spring propelled jet injectors do not offer linear delivery speeds (constant speed of the fluid being injected). In addition to this problem, spring propelled jet injectors with weak (e.g., deteriorated) springs often slow the fluid delivery speed down while the fluid is being administered into the skin which can result in improper fluid penetration. Reduced speed of the fluid can cause improper dosing and bruising at the injection site (referred to as subdermal hematoma).
In addition, if the inert gas is not quickly and properly expelled, the medication may be improperly administered like the springs. Conventional disposable needle-less injectors, such as those shown in U.S. Pat. No. 4,913,699 to Parsons and U.S. Pat. No. 5,009,637 to Newman et al. show a breakable tube that is shattered or cracked open by a side mounted trigger. Difficulties arise in the need to maintain tight tolerances on the breakable member, since minor changes in thickness can dramatically effect the pressure needed to deploy the gas from the gas chamber of the device. In addition, the broken shards of the breakable member are ejected at high speed when the gas is expelled and these shards can occasionally jam in between the plunger driver and the housing, thereby preventing proper operation of the needle-less injector. Attempts to prevent small shards from being formed would obviate some of this potential, but tend to make activation of the device more difficult.
It is an object of an embodiment of the present invention to provide improved gas power sources for a needle-less injector, syringe or the like, that obviate for practical purposes, the above-mentioned limitations.
According to an embodiment of the present invention, a needle-less injector suitable for injecting fluid through a skin surface of a patient includes a housing, a driver, an intruding gas chamber activating mechanism and a trigger. The housing containing the fluid and a sealed gas storage chamber containing a gas. The driver forces the fluid out of the housing at a sufficient speed to pierce the skin surface of the patient. The intruding gas chamber activating mechanism is mounted in the housing to intrude through the sealed gas chamber to release gas seal into the housing. The resistance sensitive trigger is operatively coupled to the intruding gas chamber activating mechanism to release the gas from the gas chamber into the housing to activate the driver to force the fluid out of the housing. The resistance sensitive trigger is activated upon application of a predetermined amount of pressure to the resistance sensitive trigger that is opposed by a predetermined amount of resistance from the skin surface of the patient. The predetermined amount of resistance results from the housing having contact with the skin surface of the patient, and when this predetermined amount of resistance is reached the fluid is forced out of the housing by the driver to pierce the skin surface of the patient. In particular embodiments, the intruding gas chamber activating mechanism includes a valve member that is displaced and intrudes into the sealed gas chamber to release the gas from the gas chamber.
In further embodiments, the housing of the needle-less injector includes a face that is adapted to align the housing to produce the predetermined amount of resistance to allow for activation of the resistance sensitive trigger. Also, the resistance sensitive trigger is preferably coupled to the housing to permit axial movement of the resistance sensitive trigger along the housing. However, the fit tolerances between the housing and the resistance sensitive trigger are selected to permit activation of the resistance sensitive trigger when the housing is aligned between 0 and 10 degrees off an axis perpendicular to the skin surface of the patient. In addition, the resistance sensitive trigger is preferably positioned to be between the skin surface of the patient and an activating appendage (such as an hand, arm or the like) of a user when activating the driver to force the fluid out from the housing.
In particular embodiments, the resistance sensitive trigger includes a resistance element that activates at a lower amount of pressure than the predetermined amount of resistance by the skin surface of the patient. For example, the resistance sensitive trigger includes a cap that is slidably attached to the housing and the resistance element includes a spring coupled between the housing and the cap. Thus, upon application of the predetermined amount of pressure to the cap of the resistance sensitive trigger, the spring compresses when the opposing resistance from the skin surface of the patient reaches the predetermined amount of resistance to activate the driver to force the fluid out of the housing to pierce the skin surface of the patient.
In additional embodiments, the housing containing the fluid includes a glass insert, a septum seal and a plunger septum to form a fluid chamber. The septum seal and the plunger septum are moved by the drive mechanism to force the fluid out of the fluid chamber. In particular embodiments, the housing further includes finger rests to support the housing as the resistance sensitive trigger activates the driver.
In further embodiments of the present invention, a needle-less injector suitable for injecting fluid through a skin surface of a patient includes a housing, a driver, a gas chamber penetrating mechanism and a trigger. The housing containing the fluid and a sealed gas storage chamber containing a gas. The driver forces the fluid out of the housing at a sufficient speed to pierce the skin surface of the patient. The gas chamber penetrating mechanism is mounted in the housing to intrude through the sealed gas chamber to release gas seal into the housing. The resistance sensitive trigger is operatively coupled to the gas chamber penetrating mechanism to release the gas from the gas chamber into the housing to activate the driver to force the fluid out of the housing. The resistance sensitive trigger is activated upon application of a predetermined amount of pressure to the resistance sensitive trigger that is opposed by a predetermined amount of resistance from the skin surface of the patient. The predetermined amount of resistance results from the housing having contact with the skin surface of the patient, and when this predetermined amount of resistance is reached the fluid is forced out of the housing by the driver to pierce the skin surface of the patient. In particular embodiments, the gas chamber penetrating mechanism includes a valve member that is displaced and penetrates the sealed gas chamber to release the gas from the gas chamber. In other embodiments, the gas chamber penetrating mechanism includes a piercing ember that penetrates the gas chamber to pierce a diaphragm in the gas chamber to release the gas from the sealed gas chamber into the housing.
In additional embodiments, the housing containing the fluid includes a glass insert, a septum seal and a plunger septum to form a fluid chamber. The septum seal and the plunger septum are moved by the drive mechanism to force the fluid out of the fluid chamber. In particular embodiments, the housing further includes finger rests to support the housing as the resistance sensitive trigger activates the driver.
According to another embodiment of the present invention, a needle-less injector suitable for injecting fluid through a skin surface of a patient includes a housing, a driver, an intruding gas chamber activating mechanism and a trigger. The housing containing the fluid, a sealed gas storage chamber containing a gas, and an orifice. The driver forces the fluid out of the orifice of the housing at a sufficient speed to pierce the skin surface of the patient. The intruding gas chamber activating mechanism is mounted in the housing to intrude through the sealed gas chamber to release gas seal into the housing. The trigger is operatively coupled to the intruding gas chamber activating mechanism to release the gas from the gas chamber into the housing to activate the driver to force the fluid out of the orifice of the housing by moving the trigger towards the orifice so that the fluid is forced out of the housing by the driver to pierce the skin surface of the patient. In particular embodiments, the intruding gas chamber activating mechanism includes a valve member that is displaced and intrudes into the sealed gas chamber to release the gas from the gas chamber.
In further embodiments, the housing of the needle-less injector includes a face that is adapted to align the housing to produce the predetermined amount of resistance to allow for activation of the trigger. Also, the trigger is preferably coupled to the housing to permit axial movement of the trigger along the housing. However, the fit tolerances between the housing and the trigger are selected to permit activation of the trigger when the housing is aligned between 0 and 10 degrees off an axis perpendicular to the skin surface of the patient. In addition, the trigger is preferably positioned to be between the skin surface of the patient and an activating appendage (such as an hand, arm or the like) of a user when activating the driver the force to fluid out from the housing.
In particular embodiments, the trigger is activated upon application of a predetermined amount of pressure to the trigger that is opposed by a predetermined amount of resistance from the skin surface of the patient. The predetermined amount of resistance results from the housing having contact with the skin surface of the patient, and when this predetermined amount of resistance is reached the fluid is forced out of the housing by the driver to pierce the skin surface of the patient. In particular embodiments, the trigger includes a resistance element that activates at a lower amount of pressure than the predetermined amount of resistance by the skin surface of the patient. For example, the trigger includes at least one actuator that is slidably attached to the housing and the resistance element includes a spring coupled between the housing and the at least one actuator. Thus, upon application of the predetermined amount of pressure to the at least one actuator of the trigger, the spring compresses when the opposing resistance from the skin surface of the patient reaches the predetermined amount of resistance to activate the driver to force the fluid out of the housing to pierce the skin surface of the patient.
In additional embodiments, the housing containing the fluid includes a glass insert, a septum seal and a plunger septum to form a fluid chamber. The septum seal and the plunger septum are moved by the drive mechanism to force the fluid out of the fluid chamber. In particular embodiments, the housing further includes finger rests to support the housing as the trigger activates the driver.
In still further embodiments of the present invention, a needle-less injector suitable for injecting fluid through a skin surface of a patient includes a housing, a driver, a gas chamber penetrating mechanism and a trigger. The housing containing the fluid and a sealed gas storage chamber containing a gas. The driver forces the fluid out of the housing at a sufficient speed to pierce the skin surface of the patient. The gas chamber penetrating mechanism is mounted in the housing to intrude through the sealed gas chamber to release gas seal into the housing. The trigger is operatively coupled to the gas chamber penetrating mechanism to release the gas from the gas chamber into the housing to activate the driver to force the fluid out of the orifice of the housing by moving the trigger towards the orifice so that the fluid is forced out of the housing by the driver to pierce the skin surface of the patient. In other embodiments, the trigger is activated upon application of a predetermined amount of pressure to the trigger that is opposed by a predetermined amount of resistance from the skin surface of the patient. The predetermined amount of resistance results from the housing having contact with the skin surface of the patient, and when this predetermined amount of resistance is reached the fluid is forced out of the housing by the driver to pierce the skin surface of the patient. In particular embodiments, the gas chamber penetrating mechanism includes a valve member that is displaced and penetrates the sealed gas chamber to release the gas from the gas chamber. In other embodiments, the gas chamber penetrating mechanism includes a piercing member that penetrates the gas chamber to pierce a diaphragm in the gas chamber to release the gas from the sealed gas chamber into the housing.
In additional embodiments, the housing containing the fluid includes a glass insert, a septum seal and a plunger septum to form a fluid chamber. The septum seal and the plunger septum are moved by the drive mechanism to force the fluid out of the fluid chamber. In particular embodiments, the housing further includes finger rests to support the housing as the resistance sensitive trigger activates the driver.
In still another embodiment of the present invention, a needle-less injector suitable for injecting a fluid through skin of a patient includes a housing, a driver and an at least partially resistance sensitive trigger. The housing contains the fluid, and includes an injection end with an orifice and a trigger portion opposite the injection end. The injection end of the housing is stationary and fixed relative to the housing. The housing also includes finger rests. The driver forces the fluid out of the orifice of the injection end of the housing at a sufficient speed to deliver the fluid to the skin of the patient. The at least partially resistance sensitive trigger is operatively coupled to the driver and the trigger portion of the housing. The movement of the partially resistance sensitive trigger activates the driver to force the fluid out of the orifice of the injection end of the housing. Upon application of a predetermined amount of pressure to the partially resistance sensitive trigger to move the partially resistance sensitive trigger relative to the housing towards the injection end and the skin and that is opposed by a predetermined amount of resistance from the skin of the patient resulting from the injection end of the housing having contact with the skin of the patient and resistance from the finger stops, the forced out fluid will be delivered to the skin of the patient. In particular embodiments, the partially resistance sensitive trigger moves closer towards the skin during an injection while the injection end and the housing remain substantially stationary relative to the skin, and the partially resistance sensitive trigger is operatively decoupled from the driver after the injection.
In further embodiments, the housing includes a face on the housing for contacting the skin of the patient and align an orientation of the housing to produce the predetermined amount of resistance to allow for activation of the partially resistance sensitive trigger. In particular embodiments, the partially resistance sensitive trigger is coupled to the housing to permit axial movement of the partially resistance sensitive trigger along the housing, wherein relative sizes of the housing and the partially resistance sensitive trigger permit activation of the partially resistance sensitive trigger when the housing is aligned between 0 and 15 degrees off an axis perpendicular to the skin of the patient. Also, the partially resistance sensitive trigger can be positioned to be between the skin of the patient and an activating appendage of a user when activating the driver to force the fluid out of the housing. In other embodiments, the partially resistance sensitive trigger includes a resistance element that activates at a lower amount of pressure than the predetermined amount of resistance by the skin of the patient. Preferably, the partially resistance sensitive trigger includes an actuator slidably attached to the housing and the resistance element includes a spring coupled between the housing and the actuator. Upon application of the predetermined amount of pressure to the cap of the partially resistance sensitive trigger the spring compresses, when the opposing resistance from the skin of the patient reaches the predetermined amount of resistance, to activate the driver to force the fluid out of the housing to penetrate the skin of the patient. In addition, the needle-less injector is compressed gas activated.
In yet another embodiment of the present invention an ampoule for use with a needle-less injector suitable for injecting fluid through skin of a patient includes a housing, a glass insert, a septum seal and a plunger septum. The housing formed from a non-glass material, and the housing forms an internal chamber. The glass insert has two ends and is contained within the internal chamber of the housing. The moveable septum seal closes off one end of the glass insert, and the moveable plunger septum closes off the other end of the glass insert to form a fluid chamber. In particular embodiments, the housing further includes an orifice, and the moveable septum seal provides a pathway for the fluid to exit the medication chamber through the orifice in the housing. In further embodiments, the housing further includes a piercing element that pierces the septum seal to form the pathway for the fluid to exit the orifice of the housing.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, various features of embodiments of the invention.